UNITED will aim to keep up their 85-year FA Cup hoodoo over Liverpool and secure a sixth-round berth in the world's oldest domestic cup competition.

Liverpool have not beaten the Reds in the FA Cup since 1921, while Rafael Benitez has yet to come out on top in four head-to-head duels with Sir Alex Ferguson.

Liverpool have also not beaten United on home soil since Michael Owen inspired the Reds to a 3-1 Premiership win in 2001.

Here is a look at the key battles which could prove pivotal to the outcome.

Jamie Carragher v Wayne Rooney

An all-Scouse duel which could turn fiery. Carragher has emerged as one of the most accomplished central defenders in the Premiership and never lets his club down. He is capable of subduing Rooney - and did so on their last meeting at Old Trafford. But, as Carragher knows only too well, there are days when his England team-mate is totally unstoppable and there is no opponent likely to ignite his talent more than Liverpool.

Harry Kewell v Gary Neville

There were plenty of critics prepared to write off Kewell's Liverpool career last summer but the Australian has proved them all wrong by producing some of the most consistent displays of his entire career recently. Given his antics in the aftermath of United's recent Premiership triumph, Neville will receive an even warmer reception from the Kop than is usually reserved for a player who epitomises everything about the club they despise. Normally unflappable, how Neville handles the reception could be decisive.

Peter Crouch v Rio Ferdinand

Few England internationals divide opinion like Peter Crouch but for all the striker's failings, Benitez feels Liverpool are a far better team with him in the side. However, Ferdinand did have him in his pocket before sauntering up to the other end to win the last clash between the sides. Crouch's height alone means Ferdinand can never be entirely confident of coming out on top in this duel and the defender's concentration levels will need to be at their sharpest.